Water glass and its process of production



Patented May 13, .1924.

UNITED STATES LOUIS SCHNEIDER, 0F BABNABD, NEW YORK.

WATER GLASS AND ITS PROCESS OF PBDDUCTION.

1T0 Drawing.

To all whom it may concern:

Be it known that I, LOUIS SCHNEIDER, of Barnard, in the county of Monroe and State of New York, have invented certain new and useful Improvements in Water Glass and its Processes of Production; and I do hereby declare the following to be a full, clear, and exact description of the same.

My invention relates to those silicates of potassium and sodium which are also known as water glasses. The object of the present invention is to simplify and cheapen the method of forming these silicates and of changing their concentration and ratio of components. Another object is to produce a process and its resultant roduct, of making the same in a more stab e form and more convenient to handle. To these and other ends the invention resides in certain improvements and combinations of arts, all as will be hereinafter more fully escribed, the novel features being pointed out in the claims at theend of the specification.

Water glass is widely used today in several im ortant industries, more often in its liquid orm or in solution: Uncertainty has been ex ressed as to the constitution of water g ass even by the more recent investigators, but it is my opinion that in the liquid form water glass is primarily a solution of sodium meta-silicate and acolloidal solution of si'licic acid, while the solid or powdered form of water glass consists of hy' drated sodium meta-silicate and a dehydrated silicic acid hydrogel. The liquid form is bulky and inconvenient for shipment and for this reason powdered water glass or an equivalent solid mixture would be more desirable because better adapted for transportation and requiring cheaper containers. But such powdered water glass is subject to, the disadvantage of being expensive to make by some of the present methods of reduction, such as the hydration, crystal ization or the dehydration processes.

This invention provides an economical solid mixture adapted to form water lass of a desired concentration upon the addition of Water in proper proportion.

The first step of my invention in the production of Water glass consists in mixing hydrated sodium oxide, or caustic soda (NaOH) with a hydrated silica or an incompletely-dehydrated-siIicic-acid -hydrogel (SiO XH O). A pure hydrated silica is preferably employed by which is meant one not readily soluble.

Application filed February 19. 1821. Serial l lo. 446,457.

that is substantially free from insoluble matter, impurities forming recipitates, and gives to its solution low tur idity and good color. The hydrated silica is selected be cause attainable in soluble form and should have a moisture content preferably. from 1 to 15% by weight to lessen the shipping weight and also to aid in dissolving. The powdered mixture thus formed is easily soluble to form the liquid water glass. If a renter than 15% moisture content is presen? in the hydrated silica the substance is not conveniently stable for some uses. I prefer to use lower than this amount of moisture in the hydrated silica because the lower the moisture content the greater will be the heat of reaction on dissolving. When much lower than about 1% of moisture is present in the hydrated silica some ortions thereof may be anhydrous and t erefore The incompletely-dehydrated-silicie acid-hydroge] may be obtained as a byproduct for example, in the preparation of sodium fluoride from hydrofluosilicic acid, or it may be found substantially purein nature. The powdered mixturejust described may be transported more readily than liquid water glass and is ada ted to form the liquid water glass merely y the addition of water. But my method is not necessarily limited to the formation of the powdered mixture since the later mentioned advantages accrue if the substantially pure incompletely dehydrated-silicic-acidhydrogel be added to a solution of sodium hydroxide directly without the formation of the powder. The powdered mixture is desirable because predetermined parts of caustic soda and hydrated'silica may be mixed to insure a water glass having the desired ratio of Na O :SiO and a desired percentage of concentration or solid centents when added to a given amount of water.

An advantage of the present method of making liquid water glass is that the ratio Na O :Si0 may be easily varied by changing the amount of the hydrated silica. Another advantage of my method of producing liquid water glass is that its concentration may be easily controlled and greater concentration thus easily and directly obtained than had been previously known. For example, by my invention a concentration or solid contents of 35% may be obtained with a 1 to 3 ratio of Na O:SiO (analytically stated). Should impure hydrated slicia be used with the sodium hydroxide to form liquid water glass, not only would objectionable impuritiesprecipitatc out of solution and require additional treatment to remove them, out some of the impurities often n'eei 'iitate out and jcll, and because of the latter condition prevent the formation of the desired ratio of M 0510 solid content or viscosity. With the incompletelyalchydrated-silieic-acid-hy" drogel a desired ratio of Na. i() may he obtained more easily in concentrations than heretofore. In fttl'll'ltltlflll of the liquid water glass from my mixture. additional pressure or heat is not necessary. but higher tcn'lperatures may he used in it is desired to hasten the process. I

The powdered water glass or the mixture described above has the advantage that it may he formed into a block, cake, or tablet by the application of great pressure, preferably from Loon to 10.000 pounds per square inch for a short period ot time, say 4 or 5 seconds. or longenough to allow the air to be forced out. All data or values given in this s 'iecilication for pressure, time, percentage of moisture. density, etc., are true for a 1 to 3 ratio of the Na Ozsio but my invention covers other ratios than this.

The (Oll'llNHllKlS of potassium and their use to form water glass is regarded as the equivalent of the compounds of sodium referred to in the, foregoing specification and throughout the appended claims.

I claim as my invention:

1. 'lhefproecss of making water glass by mixing in a dry state caustic soda with an inemnpletely dehydrated-st]icic-acid-hydrogel and suhserpiently adding water to produce the desired concentration.

2. The process of making water glass by mixing in a dry state solid caustic soda with solid hydrated silica and adding, water to produce the desired conccntrat ion.

3. A mixture of powdered caustic soda 11d powdered iucomplctelydehydrated-sh l1-iearid-hydrogel winch is stable and cone pletely soluble.

4. The process of making a powdered mixture for producing water glass adapted to silica give different values for the ratio NaO :SiO which comprises mixing in a dry state di'f t'erent quantities of dehydrated-silicicacidlrvdrogel with caustic soda.

5. The process of making water glass which comprises mixing, in a dry state hydrated sodium oxide with a completely soluble hydrated silica, and adding water in proper proportion to obtain the desired concentration.

(i. The process of making solid water glass which comprises mixing powdered caustic soda with a powdered incompletely-dehydrated-silicic-acid-hydrogel having a water content of substantially 1 to 15 per cent.

7. The process of forming water glass havin a ratio 'Nai ,():nSiO in which n has a va ac substantially of from 1 to 3, which comprises selecting a predetermined uantity of an incompletely-dchydrated-siicicacid-hydrogel and mixing the same with a. definite amount of caustic soda and adding water in the proper proportion to obtain the desired concentration.

8. The process of makin water glass by mixing hydrated sodium oxide and hydrated aving a moisture content of not more than 15% by \vei ht, and subsequently add ing water to pro uce the desired concentration.

9. A mixture of hydrated sodium oxide, and hydrated silica havin a moisture content of not more than 15% weight, adapted to forms. liquid water ass of a desired concentration upon the ad ition of a proper quantity of water.

10. The recess of making water glass by mixing; so 1d caustic soda, and hydrated silica iaving a moisture content of not more than 15% by weight, and subsequently adding water to produce the desired concentration.

11. A mixture of solid caustic soda and hydrated silica havin a moisture content of not more than 157(5) weight adapted to form a liquid water glass of a desired concentration. upon the addition of a proper quantity of water.

LOUIS SCHNEIDER. 

